According to a report in the British Journal of Nutrition, researchers from the University of Liverpool found that the omega-3s found in fish oil could prevent fats from interrupting neurogenesis, a process that generates new nerve cells.
“Excessive intake of certain macronutrients, the refined sugars and saturated fats found in junk food, can lead to weight gain, disrupt metabolism and even affect mental processing,” explained study co-author Lucy Pickavance, from the university’s Institute of Aging and Chronic Disease. ”These changes can be seen in the brain’s structure, including its ability to generate new nerve cells, potentially linking obesity to neurodegenerative diseases.
“Research, however, has suggested that omega-3 fish oils can reverse or even prevent these effects,” Pickavance added. “We wanted to investigate the literature on this topic to determine whether there is evidence to suggest that omega-3s might aid weight loss by stimulating particular brain processes.”
To investigate the role played by omega-3s in the context of a high-fat diet, the British researchers culled data from 185 separate studies and found certain hormones that are secreted after eating, designed to protect neurons and stimulate their growth, are restricted from passing into the brain by the inflammatory effects of fatty triglycerides.
The team also found the number molecules capable of stimulating nerve growth are also reduced, but omega-3s restore normal function through the interference of inflammatory molecules, the supression of triglycerides, and by returning these nerve growth factors to normal levels.
“Fish oils don’t appear to have a direct impact on weight loss, but they may take the brakes off the detrimental effects of some of the processes triggered in the brain by high-fat diets,” added Pickavance. “They seem to mimic the effects of calorie restrictive diets and including more oily fish or fish oil supplements in our diets could certainly be a positive step forward for those wanting to improve their general health.”
The scientific community appears to have a love-hate relationship with fish oil supplements, with studies emerging on an almost weekly basis that either support or deny their health benefits. While the University of Liverpool study shows one benefit of omega-3s, another study published in the New England Journal of Medicine this month suggested that previously thought cardiovascular benefits of the popular supplement may have been overblown.
According to the study, which included over 12,000 people, fish oil supplements showed no benefit with respect to reducing hospital admissions for cardiovascular disease.
However, previous research has shown fish oil supplements could lower heart disease risks in people who have already suffered a heart attack. The American Heart Association guidelines still recommend fish oil or omega-3 supplements only for people who have high levels of triglycerides in their blood.
Some experts have pointed out the exclusion of confounding factors in fish oil studies, such as participants’ diet, smoking or exercise habits, adding that supplement takers may simply have an all-around healthier approach to life.